Technical data January 2017 MTL surge protection EPS 901-107 Rev U MTL SD range Ultra-slim user-friendly devices for protecting electronic equipment and systems against surges on signal and I/O cabling. Range of ATEX Certified intrinsically safe surge protectors Ultra-slim space-saving design easy installation Multistage hybrid protection circuitry 20kA maximum surge current Range of voltage ratings to suit all process I/O applications High bandwidth, low resistance, RTD, PSTN and 3-wire transmitter versions available 10 year product warranty The SD range is a series of surge protection devices combine For three wire applications the specially designed SDRTD unparalleled packing densities, application versatility, proven (Resistance Temperature Detector) and the SD32T3, (for separately reliable hybrid circuitry, simple installation and optional loop powered 4-20mA loops) provide full 3-wire protection in a single disconnect facilities features which make the range the ultimate compact unit. The recommended choice for the protection of surge protection solution for process equipment, I/O systems and 3-wire pressure transducers on low power circuits is the SD07R3. communications networks. For higher bandwidth applications, the SDR range has been The exceptionally high packing densities are the consequence developed to meet the demands of todays highest speed of an ultra slim footprint for individual modules which can thus communication systems. double-up as feedback terminals. Each module provides full 120V and 240V AC versions are available for I/O and power hybrid surge protection for 2 and 3 wire loop protection. supplies up to three Amps of load current and telephone networks Modules with a comprehensive range of voltage ratings cover can be protected by the SDPSTN. all process related signals such as RTDs, THCs, 4 to 20mA loops, One simple manual operation clamps modules securely onto DIN telemetry outstations, shut-down systems and fire and gas rail, which automatically provides the essential high-integrity detectors. earth connection. Optional loop disconnect, is a feature which allows Top-hat (T-section) DIN rail is generally suitable for mounting SD commissioning and maintenance to be carried out without modules although for adverse environments, a specially-plated removal of the surge protection device. This facility is provided version is available. A comprehensive range of mounting and by the SD07, SD16, SD32 and SD55 units. In addition, a third earthing accessories can also be supplied, see page 7 for further connection on the field and safe side of the protector is provided details. in order to terminate screens safely. Eaton Electric Limited, Great Marlings, Butterfield, Luton Beds, LU2 8DL, UK. Tel: + 44 (0)1582 723633 Fax: + 44 (0)1582 422283 E-mail: mtlenquiry eaton.com www.mtl-inst.com 2017 Eaton All Rights Reserved Publication No. EPS 901-107 Rev U January 2017 1MTL SD range January 2017 Guide to applications and selection The SD range of SPDs includes models for almost all possible multiple loops. The individual module fuse prevents a fault applications operating at voltages up to 250V AC. The optional or follow on current on one loop disrupting the power supply to the others. Also, loops can be removed from the circuit for fuse/disconnect package provides both fused protection against fault currents and a convenient method of isolating field circuitry maintenance reasons or added without needing additional disconnect terminals. from protected circuitry without needing additional disconnect terminals. The standard fuse (which is replaceable) is rated The following guide to selection suggests the most suitable 250mA with 50mA fuses also being available by special request. SDs for a number of specific applications. For technical Where only the disconnect feature is required, solid links can be information, see the detailed specifications on the back page used. of this publication (some field circuit protection is shown for completeness). As an example, this feature is of particular value in applications in which an SPD is used with a bulk power supply feeding FIELD CIRCUIT PROTECTED CIRCUIT Analogue inputs (high-level) 2-wire transmitters, 4-20mA, conventional and smart The SPDs recommended for use with conventional and smart 4-20mA transmitters (fed by a well-regulated supply) are the SD32 and SD55, the choice depending upon the maximum working voltage of the system (32V and 55V respectively). The diagram illustrates a prime example of an application for which the fuse/disconnect facility is particularly useful, however, both models are available in X versions without the optional fuse/disconnect feature. 2-wire transmitters Analogue inputs (low-level) RTDs These applications are best served using the SDRTD. For optimum accuracy, the energising current should be chosen to ensure the voltage across the RTD does not exceed 1V over the full measurement range. When using a PT100 device, we recommend an energising current of 1mA. 3-wire RTDs Photocells, THCs, mV sources and turbine flowmeters The SD07 or SD16 (depending upon the operational voltage) are the favoured choices for this application. SD07X and SD16X are also suitable. Photocells, THCs, mV sources and turbine flowmeters 2 www.mtl-inst.com